Where does the gas fueling star formation in BCGs originate?

We investigate the relationship between X-ray cooling and star formation in brightest cluster galaxies (BCGs). We present an X-ray spectral analysis of the inner regions, 10-40 kpc, of six nearby cool core clusters (z<0.35) observed with Chandra ACIS. This sample is selected on the basis of the high star formation rate (SFR) observed in the BCGs. We restrict our search for cooling gas to regions that are roughly cospatial with the starburst. We fit single- and multi-temperature mkcflow models to constrain the amount of isobarically cooling intracluster medium (ICM). We find that in all clusters, below a threshold temperature ranging between 0.9 and 3 keV, only upper limits can be obtained. In four out of six objects, the upper limits are significantly below the SFR and in two, namely A1835 and A1068, they are less than a tenth of the SFR. Our results suggests that a number of mechanisms conspire to hide the cooling signature in our spectra. In a few systems the lack of a cooling signature may be attributed to a relatively long delay time between the X-ray cooling and the star burst. However, for A1835 and A1068, where the X-ray cooling time is shorter than the timescale of the starburst, a possible explanation is that the region where gas cools out of the X-ray phase extends to very large radii, likely beyond the core of these systems.Comment: to appear in A&

A textbook example of ram-pressure stripping in the Hydra A/A780 cluster

In the current epoch, one of the main mechanisms driving the growth of galaxy clusters is the continuous accretion of group-scale halos. In this process, the ram pressure applied by the hot intracluster medium on the gas content of the infalling group is responsible for stripping the gas from its dark-matter halo, which gradually leads to the virialization of the infalling gas in the potential well of the main cluster. Using deep wide-field observations of the poor cluster Hydra A/A780 with XMM-Newton and Suzaku, we report the discovery of an infalling galaxy group 1.1 Mpc south of the cluster core. The presence of a substructure is confirmed by a dynamical study of the galaxies in this region. A wake of stripped gas is trailing behind the group over a projected scale of 760 kpc. The temperature of the gas along the wake is constant at kT ~ 1.3 keV, which is about a factor of two less than the temperature of the surrounding plasma. We observe a cold front pointing westwards compared to the peak of the group, which indicates that the group is currently not moving in the direction of the main cluster, but is moving along an almost circular orbit. The overall morphology of the group bears remarkable similarities with high-resolution numerical simulations of such structures, which greatly strengthens our understanding of the ram-pressure stripping process

The evolving cluster cores: Putting together the pieces of the puzzle

In this work we address the issue of whether the division of clusters in cool cores (CCs) and non-cool cores (NCCs) is due to a primordial difference or to how clusters evolve across cosmic time. Our first goal is to establish if spectra from the central regions of a subclass of NCCs known as cool core remnants (CCRs) are consistent with having a small but significant amount of short cooling time gas, thereby allowing a transformation to CC systems on a timescale of a giga year. Our second goal is to determine if low ionization Fe lines emitted from this residual cool gas will be detectable by the calorimeters that will fly on board XRISM and ATHENA. We performed a spectral analysis of CCR systems with a multi temperature model and, assuming the different components to be in pressure equilibrium with one another, derived entropy and cooling time distributions for the X-ray emitting gas. We find that in most of our systems, the spectral model allows for a fraction of low entropy, short cooling time gas with a mass that is comparable to the one in CC systems. Moreover, simulations show that future spectrometers on board XRISM and ATHENA will have the power to directly resolve emission lines from the low temperature gas, thereby providing incontrovertible evidence for its presence. Within the scenario that we have explored, the constant fraction of CCs measured across cosmic time emerges from a dynamical equilibrium where CCs transformed in NCCs through mergers are balanced by NCCs that revert to CCs. Furthermore, CCs and NCCs should not be viewed as distinct sub classes, but as ``states" between which clusters can move.Comment: To appear in Astronomy & Astrophysic

Role of 0.4% glyceryl trinitrate ointment after haemorrhoidectomy: results of a prospective randomised study

INTRODUCTION: Conventional haemorrhoidectomy (CH) is well known to cause significant post-operative pain and delayed return to daily activities. Both surgical wounds and sphincterial apparatus spasms are likely responsible for the pain. In this study, we evaluated the role of glyceryl trinitrate ointment (GTN) in reducing post-operative pain, ameliorating wound healing and recovery after CH. PATIENTS AND METHODS: Between 01/08 and 12/11, 203 patients with symptomatic haemorrhoids were enrolled in the study and received (103 patients) or not (100 patients) 0.4 % GTN ointment for 6 weeks after surgery. Pain was assessed using a 10-cm linear visual analogue scale (VAS). Data on post-operative pain, wound secretion and bleeding, return to normal activities and complications were recorded. Data were analysed using Fisher's exact and Mann-Whitney tests. RESULTS: GTN-treated group experienced significantly less pain during the first week after surgery (p < 0.0001). This difference was more evident starting from post-operative day 4 (p < 0.0001). A significant higher percentage of untreated patients experienced severe pain (mean VAS score > 7) (10 % vs 31 %). There were significant differences in terms of secretion time (p = 0.0052) and bleeding time (p = 0.02) in favor of GTN. In addition, the duration of itching was less in the GTN group (p = 0.0145). Patients treated with GTN were able to an early return to daily activities compared to untreated (p < 0.0001). Fifteen GTN-treated patients (14.6 %) discontinued the application because of local discomfort and headache. CONCLUSIONS: GTN ointment enhances significantly post-operative recovery, reducing pain in terms of duration and intensity. This effect might be secondary to a faster wound healing expressed by reduced secretion, bleeding and itching time

In gravidanza: studio epidemiologico sugli aspetti ansiosi e depressivi

Il percorso formativo di un\u2019ostetrica ha da sempre sottolineato l\u2019attenzione alla sfera emotiva della persona, quale punto di forza della sua arte e del suo \u2018saper essere\u2019, nell\u2019incontro empatico con l\u2019altro. La scelta di approfondire la tematica dei disturbi ansiosi e depressivi, si pone a difesa di quell\u2019intimo contatto e di quella protezione essenziale nei confronti dell\u2019io delle donne, cui la figura dell\u2019ostetrica \ue8 preposta. L\u2019obiettivo di questo lavoro si incentra principalmente sull\u2019evidenza di una necessit\ue0 reale di supporto emotivo alle donne gi\ue0 nel corso della gravidanza, e poi successivamente nel puerperio. Lo studio epidemiologico mira a porre l\u2019accento sull\u2019effettivo riscontro di sintomatologie depressive o ansiose nel corso del periodo gestazionale, quali specchio di un\u2019incertezza diffusa, di un bisogno silente di attenzione e cura. Si mira cos\uec a rendere coscienti gli operatori sanitari dell\u2019evidente necessit\ue0 di supporto e informazione alle future madri, spingendo in particolare le ostetriche nella direzione di un\u2019assistenza completa, che includa una pi\uf9 scrupolosa attenzione alla sfera emotiva della persona. Lo studio intrapreso si pone come indagine epidemiologica e di screening, inserita all\u2019interno di un progetto pi\uf9 ampio, volto alla sensibilizzazione ad un tema tanto complesso quanto poco indagato nella pratica clinica. Il fine ultimo \ue8 quello di proporre l\u2019istituzione di un vero e proprio servizio di supporto dedicato alle donne in gravidanza ed alle mamme nel dopo parto, volto all\u2019approfondimento della tematica della depressione e dell\u2019ansia, alla prevenzione ed alla cura dei disturbi di tipo psichico, ed all\u2019adattamento sereno alla condizione di maternit\ue0

Iron in x-cop: Tracing enrichment in cluster outskirts with high accuracy abundance profiles

We present the first metal abundance profiles for a representative sample of massive clusters. Our measurements extend to R500 and are corrected for a systematic error plaguing previous outskirt estimates. Our profiles flatten out at large radii, admittedly not a new result, however the radial range and representative nature of our sample extends its import well beyond previous findings. We find no evidence of segregation between cool-core and non-cool-core systems beyond 3c0.3\ue2 R500, implying that, as was found for thermodynamic properties, the physical state of the core does not affect global cluster properties. Our mean abundance within R500 shows a very modest scatter, < 15%, suggesting the enrichment process must be quite similar in all these massive systems. This is a new finding and has significant implications for feedback processes. Together with results from the thermodynamic properties presented in a previous X-COP paper, it affords a coherent picture in which feedback effects do not vary significantly from one system to another. By combining intra-cluster medium with stellar measurements we have found the amount of Fe diffused in the intra-cluster medium to be about ten times higher than that locked in stars. Although our estimates suggest, with some strength, that the measured iron mass in clusters is well in excess of the predicted one, systematic errors prevent us from making a definitive statement. Further advancements will only be possible when systematic uncertainties, principally those associated with stellar masses, both within and beyond R500, can be reduced